Wheel rim and assembly of wheel rim and tire

ABSTRACT

The present invention relates to a rim and an assembly of the rim and a tire which are applicable to both a safety tire and a conventional tire. The object of the present invention is to provide a rim and an assembly which enable safe running even when the inner pressure of the tire is lowered or when the vehicle is cornering sharply, and which are usable with not only a safety tire but also with conventional tires. A wheel rim and an assembly of the rim and tubeless tire of the present invention are characterized in that an annular groove (3) is provided axially outside a well (2) in such a manner as to extend in the circumferential direction, and a hump (4) is provided axially outside the annular groove in such a manner as to extend in the circumferential direction. The tubeless tire is characterized by being provided with a toe portion (13) and a hump groove (14) which are adapted to engage the annular groove (3) and the hump (4), respectively.

TECHNICAL FIELD

The present invention relates to a rim applicable to both a safety tireand an ordinary tire and an assembly of the rim and the safety tire and,more particularly, to an assembly of a wheel and a tire which enablesthe safe running of the tire free from the danger of the bead portion ofthe tire coming off the rim when the inner pressure of the tire isreduced or while the vehicle is turning (cornering) sharply.

BACKGROUND ART

In an assembly of a tire and a wheel rim, the tire bead portion isconventionally held to the beadbase by virtue of the pressing force ofthe inner pressure of the tire and the frictional force between thebeadbase and the rubber of the bottom portion of the tire bead.Therefore, if the inner pressure of the tire is lowered, this holdingforce is reduced and, specifically, if the vehicle steers sharply with arapidly lowered inner pressure caused by, for example, a puncture, therim comes off the bead portion due to a force produced in the transversedirection generated by the turning operation. In particular, a rimprovided with a well for mounting a tire involves the danger of bringingabout a serious accident when the bead portion of the tire drops intothe well and thereby completely comes off the rim. More specifically,the mechanism of the bead portion of a tire coming off the rim can beexplained as follows.

The force in the transverse direction caused when a vehicle is corneringdeviates the tread portion in the transverse direction relative to thewheel rim and produces deformation on the tread portion. Thisdeformation is transmitted from the carcass to the bead portion of thetire. As a result, in the vicinity of the portion of the tire whichcomes into contact with the ground, a force is caused in the directionof the rotating axis of the tire (hereinunder referred to as "axialdirection") and also a turning moment is produced around thecircumference of the bead.

At this time, if the inner pressure of the tire is low, since theseforces lift the heel of the bead portion, the frictional force betweenthe bottom portion of the bead and the beadbase, which is the beadportion holding force, is reduced. As a result, the bead portion moveson the tapered bead base inwardly in the axial direction, and thetension of the bead core is also reduced with the movement of the beadportion. The bead portion holding force is therefore rapidly lost,whereby the bead portion drops into the well. To solve this problem, theuse of a rim having no well, the use of a rim provided with a hump atthe portion which comes into contact with the bead toe so as to preventthe bead portion from moving inwardly in the axial direction, anassembly of a tire and a rim having a hump provided in the beadbase andan annular groove provided at the bead bottom portion of the tire so asto be engaged with the hump (Japanese Patent Laid-Open No. 13802/1974),and an assembly of a tire and a rim having an annular groove providedaxially inside the beadbase and a hump provided on the bead toe so as tobe engaged with the annular groove (Japanese Patent Publication No.15007/1982) have been proposed. Among these, the assembly disclosed inthe Japanese Patent Publication No. 15007/1982 has an excellent effectas a bead holding mechanism.

Such an assembly, however, has a special configuration at the portion atwhich the rim comes into contact with the bead portion of the tire. Itis therefore impossible to use a conventional tire with such a rim, andif a conventional tire is used by mistake, there is a problem in termsof safety.

Accordingly, it is an object of the present invention to provide a wheelrim and an assembly of a wheel rim and a tire which are capable ofmaintaining the bead portion holding mechanism of a tire when the innerpressure of the tire is lowered and which are also capable of utilizinga tire having a conventional structure.

DISCLOSURE OF THE INVENTION

In one aspect of the present invention, there is provided a wheel rimcharacterized by an annular groove which is provided axially outside awell for mounting a tire in such a manner as to extend in thecircumferential direction, and a hump which is provided axially outsidethe annular groove in such a manner as to extend in the circumferentialdirection.

In another aspect of the present invention there is provided an assemblyof a tubeless tire having a pair of bead portions and a wheel rim havinga well for mounting a tire, wherein at least one of the bead portions isprovided with a non-stretching bead core and a hump groove annularlyformed between the bead core and a toe portion which is provided axiallyinside the bead core in such a manner as to extend inwardly in theradial direction. The wheel rim is provided with an annular groove forreceiving the tip of the toe portion and a hump formed axially outsidethe annular groove.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus, are notlimitative of the present invention, and wherein:

FIG. 1 is a partial sectional view of a wheel rim according to thepresent invention;

FIG. 2 is a partial sectional view of an assembly of a wheel rim and atire according to the present invention, wherein the reference numeral 4represents a hump of the wheel rim, element 3 an annular groove of thewheel rim, element 13 a toe portion of the tire and 14 a hump groove ofthe tire;

FIG. 3 shows an example of application of the present invention;

FIG. 4 is a sectional view of an assembly of a wheel rim according tothe present invention with a conventional ordinary tire mounted thereon;and

FIG. 5 is a sectional view of an assembly according to the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be explained in more detail hereinunder withreference to the accompanying drawings.

In FIG. 1, a wheel rim 1 is provided with a well 2 for mounting a tire.An annular groove 3 extending in the circumferential direction isprovided axially outside the well forming an inner protrusion 7, andhump 4 extending in the circumferential direction of a tire is formedaxially outside the annular groove 3. Axially outside the hump 4, abeadbase 5 and a rim flange 6 are provided.

It is possible to facilitate the mounting of a tire on the wheel rim bytapering the beadbase 5 at a predetermined angle α with respect to theaxial direction M. The angle α is preferably in the range of 2° to 10°.If it is less than 2°, it is difficult to mount a tire on the wheel rim,while if it exceeds 10°, the bead portion too easily drops into thewell, thereby lowering the bead holding force.

The diameters Da, Db, Dc of the wheel rims at the top 4e of the hump,the bottom 3e of the annular groove, and the top 7e of the innerprotrusion, respectively, and the diameter D of the beadbase preferablyhave the following relationships:

    -3.0 mm≦D-Da≦+5.0 mm

    +2.0 mm≦D-Db≦+20 mm

    0 mm≦D-Dc≦+5.0 mm

If D-Da>+5.0 mm, D-Db<+2.0 mm or D-Dc>5.0 mm, it is difficult to obtaina desirable bead holding mechanism, and if D-Da<-3.0 mm or D-Dc<0 mm,the operation of mounting a tire on the wheel rim is difficult. IfD-Db>+20 mm, it is difficult to produce a wheel rim having adequatedurability.

The diameter D of the beadbase here means the diameter of the wheel rimat the base end H which is the intersecting point of the extensions ofthe beadbase 5 and the inner surface of the flange 6.

It is further possible to facilitate the mount of a tire on the wheelrim by setting the diameters Da, Db and Dc of the rim at the respectivepoints so as to provide the relationship Da>Dc>Db.

FIG. 3 shows another example of application of the present invention. Abeadbase 5a is inversely tapered at an angle of -β° with respect to theaxial direction, and a hump 4a is provided continuously at the inner endof the beadbase 5a without any particular protrusion. The angle -β ispreferably in the range of -10° to -2°. If it is more than -2°, it isdifficult to obtain the necessary holding force, while if it is under-10°, the force applied to the flange portion becomes so large as tonecessitate a special configuration for reinforcing the flange portion.

FIG. 2 is a partial sectional view of an assembly of a wheel rimaccording to the present invention and a tire 11. In FIG. 2, the bead ofthe tire is provided with a non-stretching core 12, a toe portion 13formed axially inside of the bead core 12 and extending inwardly in theradial direction, and a hump groove 14 formed axially outside the toeportion 13. The toe portion 13 and the hump groove 14 are engaged withthe annular groove 3 and the hump 4, respectively, of the wheel rim,whereby it is possible to prevent the bead portion from being movedinwardly in the axial direction by a force in the transverse directioncaused during cornering of the vehicle when the inner pressure of thetire is low.

It is necessary to set the configuration and the dimension of the toeportion 13 and the configuration and the dimension of the hump groove 14in the correspondence with the configurations and the dimensions of theannular groove 3 and the hump 4, respectively. It goes without sayingthat a bead apex 15 and a bead reinforcing chafer 16 are applicable tothe bead portion in accordance with the purpose, as in a conventionaltire. The rubber of the toe portion is preferably a comparatively hardrubber having a hardness of, for example, JIS-A 70° to 95°. It isfurther possible to form the chafer 16 in such a manner as to envelopthe toe portion 13.

It is possible to enhance the bead portion holding force of the assemblyaccording to the present invention by establishing the followingrelationships between the axial distance W3 from the heel end J of thetire 11 to the bottom 14e of the hump groove 14 and the axial distanceW1 from the base end H of the beadbase to the top 4e, and between theaxial distance W4 from the heel end J to the end N of the toe portion 13and the axial distance W2 from the base end H to the bottom 3e of theannular groove 3, respectively:

    0.5≦W3/W1≦1.2

    0.7≦W4/W2≦1.2

FIG. 4 shows an example of a wheel rim according to the presentinvention which is applied to a conventional tire. The width W5 of thebeadbase may be any dimension of a rim which is conventionallystandardized. Thus, a wheel rim according to the present invention isadvantageous in that although it adopts the above-described specialstructure, it is applicable to a tire having a conventional structure.

FIG. 5 shows a sectional view of an assembly according to the presentinvention, in which the above-described special structure is adopted tothe bead portions on both sides. Needless to say, it is possible toadopt the special structure only to one bead portion.

The present invention is applicable to various vehicles such aspassenger cars, motorbikes, tricycles, ATVs, trucks and buses.

The dimensions of the examples of application of the present inventionto the tires and wheel rims for passenger cars, a motorbike, and an ATVare shown in Table 1.

                                      TABLE 1                                     __________________________________________________________________________              Example 1                                                                            Example 2                                                              Passenger                                                                            Passenger                                                                           Example 3                                                                            Example 4                                                 Car (1)                                                                              Car (2)                                                                             Motorbike                                                                            ATV                                             __________________________________________________________________________    Wheel Rim                                                                           Size                                                                              6.5 × 15                                                                       6 × 15                                                                        4.00 × 17                                                                      9 × 9.0                                         D   380.2 mm                                                                             380.2 mm                                                                            433.8 mm                                                                             227.8 mm                                              Da  379.2 mm                                                                             379.2 mm                                                                            433.12 mm                                                                            229.4 mm                                              Db  368.2 mm                                                                             370.2 mm                                                                            423.8 mm                                                                             215.8 mm                                              Dc  376.2 mm                                                                             377.2 mm                                                                            429.8 mm                                                                             223.8 mm                                              α                                                                           5°                                                                            5°                                                                           5°                                                                            5°                                             W1  22.0 mm                                                                              22.0 mm                                                                             16.0 mm                                                                              15.0 mm                                               W2  32.0 mm                                                                              31.5 mm                                                                             22.0 mm                                                                              25.0 mm                                         Tire  Size                                                                              205/65R15                                                                            215 SR15                                                                            150/70-17                                                                            25 × 12.00-9                                    W3  17 mm  18.5 mm                                                                             15.5 mm                                                                              15 mm                                                 W4  27.5 mm                                                                              28.5 mm                                                                             21.5 mm                                                                              27 mm                                           __________________________________________________________________________

The respective tires and wheel rims were produced according to thespecifications shown in Table 1, and indoor tests and running tests werecarried out, thereby confirming the effects of the present invention.

Table 2 shows examples of the present invention and a comparativeexample of tires and wheel rims for a passenger car. Example 1--1 is anassembly of a wheel rim and a tire of the present invention, Example 1-2an assembly of a wheel rim of the present invention and a conventionaltire, and Comparative Example 1 an assembly of conventional wheel rimand tire, the tire being 205/65 R 15 and the rim 6.5 in. ×15 in. insize.

The bead dislodgement forces of these three assemblies were measured byan indoor testing machine when air leakage or bead dislodgement wascaused by applying a force in the transverse direction to the treadportions under the three conditions that the inner pressure was 0kg/cm², 1.0 kg/cm² and 2.0 kg/cm², respectively.

                  TABLE 2                                                         ______________________________________                                        [Tires and Wheel Rims for a Passenger Car (1)]                                           Example            Comparative                                                1-1     Example 1-2                                                                              Example 1                                       ______________________________________                                        Wheel Rim                                                                             Size     6.5 × 15                                                                          6.5 × 15                                                                         61/2 JJ × 15                                D        380.2 mm  380.2 mm                                                   Da       379.2 mm  379.2 mm Conventional                                      Db       368.2 mm  368.2 mm Rim                                               Dc       376.2 mm  376.2 mm                                                   α  5° 5°                                                  W1       22.0 mm   22.0 mm                                                    W2       32.0 mm   32.0 mm                                            Tire    Size     205/65R15 205/65R15                                                                              205/65R15                                         W3       17 mm     Conventional                                                                           Conventional                                      W4       27.5 mm   Tire     Tire                                      **I.P.       *B.D.F                                                           Indoor Test                                                                           0        680       380      200                                               1.0      1240      900      810                                               2.0      2235      1770     1500                                      ______________________________________                                         *B.D.F. . . . Bead Dislodgement Force (kg)                                    **I.P. . . . Inner Pressure (kg/cm.sup.2)                                

Example 1--1 of the present invention exhibited a prominent beaddislodgement capacity. In the case of mounting a conventional tire onthe wheel rim according to the present invention a slight effect wasalso exhibited on the bead dislodgement capacity, as is clear from theresults of the Example 1-2, and the assembly was found to be practicallyusable without a problem.

Table 3 shows examples of the present invention and a comparativeexample of other tires and wheel rims for a passenger car. Examples 2-1and 2--2 are assemblies of wheel rims and tires according to the presentinvention, Example 2-3 an assembly of a wheel rim of the presentinvention and a conventional tire, and Comparative Example 2 an assemblyof a conventional wheel rim and a conventional tire, the tire being 215SR15 and the rim 6 in. ×15 in. in size. The tires and wheel rims in theexamples were produced specifically for a car with four-wheel drive.

                                      TABLE 3                                     __________________________________________________________________________    [Tires and Wheel Rims for a Passenger Car (2)]                                            Example                                                                             Example                                                                            Example                                                                              Comparative                                                 2-1   2-2  2-3    Example 2                                       __________________________________________________________________________    Wheel Rim                                                                           Size  6 × 15                                                                        6 × 15                                                                       6 × 15                                                                         6 JJ × 15                                       D     380.2 mm                                                                            380.2 mm                                                                           380.2 mm                                                     Da    379.2 mm                                                                            379.2 mm                                                                           379.2 mm                                                                             Conventional                                          Db    370.2 mm                                                                            370.2 mm                                                                           370.2 mm                                                                             Rim                                                   Dc    377.2 mm                                                                            377.2 mm                                                                           377.2 mm                                                     α                                                                             5°                                                                           5°                                                                          5°                                                    W1    22.0 mm                                                                             22.0 mm                                                                            22.0 mm                                                      W2    31.5  31.5 mm                                                                            31.5 mm                                                Tire  Size  215/SR15                                                                            215/SR15                                                                           215/SR15                                                                             215/SR15                                              W3    18.5 mm                                                                             18.5 mm                                                           W4    28.5 mm                                                                             28.5 mm                                                           Hardness         Conventional                                                                         Conventional                                          of Toe                                                                              78°                                                                          64°                                                                         Tire   Tire                                                  Portion                                                                 **I.P.      *B.D.F.                                                           Indoor Test                                                                         0     690   650  340    200                                                   1.0   1730  1320 930    840                                                   2.0   1800  1800 1500   1270                                            __________________________________________________________________________     *B.D.F. . . . Bead Dislodgement Force (kg)                                    **I.P. . . . Inner Pressure (kg/cm.sup.2)                                

These examples show that the present invention has prominent effects onthe bead displacement capacity as in the examples in Table 2. In thecase of mounting a conventional tire on the wheel rim according to thepresent invention a slight effect was also exhibited on the beaddislodgement capacity, and the assembly was found to be practicallyusable without a problem. It was also found from Examples 2-1 and 2--2that a tire having a harder toe portion exhibits a higher effect,specifically, when the inner pressure is low. The effects of the presentinvention were further confirmed by running tests. The results are shownin Table 4.

                                      TABLE 4                                     __________________________________________________________________________    Tires and Wheel Rims for a                                                                     Tires and Wheel Rims for a                                   Passenger Car (1)                                                                              Passenger Car (2)                                            Ex. 1-1   Comp. Ex. 1    Ex. 2-1                                                                            Comp. Ex. 2                                     __________________________________________________________________________    *I.P 0.0  0.8    Turning Speed                                                                         ** TN/D                                                                            ** TN/D                                         (kg/cm.sup.2)    30 km/h 2/NO 2/NO                                                             35 km/h 2/NO 2/NO                                                             40 km/h 10/NO                                                                              3/YES                                           __________________________________________________________________________     *I.P. . . . Inner Pressure When Bead Dislodgement Occurred                    **TN . . . Number of Turns                                                    D . . . Bead Dislodgement Occurred                                       

In the left column of Table 4 the results of the tests of the tires andwheel rims for a passenger car of Example 1--1 and Comparative Example 1in Table 2 are shown. The respective assemblies of the tires and wheelrims were mounted on the right front wheel of a Japanese passenger carhaving a displacement of 3 l. The inner pressure was gradually reducedin a J turn test in which the wheel was sharply turned left on thecircumference of a circle of 25 m in radius at a speed of 60 km/h,thereby causing bead dislodgement. In these tests, bead dislodgement wascaused in the assembly of Comparative Example 1 when the inner pressurewas 0.8 kg/cm², while it was not until the inner pressure was 0 kg/cm²,in other words, until the tire completely punctured that beaddislodgement was caused in the assembly of Example 1--1.

In the right column of Table 4 the results of the tests of other tiresand wheel rims for a passenger car of Example 2-1 and ComparativeExample 2 in Table 3 are shown. After the respective tires and wheelrims were completely assembled, the inner pressure was reduced to 0kg/cm². The respective assemblies were mounted on the the right frontwheel of a Japanese car with four-wheel drive having a displacement of 4l. Whether or not bead dislodgement occurred was examined in a J turntest in which the wheel was sharply turned left on the circumference ofa circle of 30 m in radius at speeds of 30 km/h, 35 km/h and 40 km/h,respectively. In these tests, bead dislodgement was caused in theassembly of Comparative Example 2 when the wheel turned 3 times at aspeed of 40 km/h, while no bead dislodgement was caused in the assemblyof Example 2-1 even after the wheel turned 10 times at a speed of 40km/h.

It goes without saying that application of the present invention doesnot impair other performances of a tire. As an example, the results ofthe comparison between the performances of a tire in Examples 1--1 andComparative Example 1 are shown in Table 5.

                  TABLE 5                                                         ______________________________________                                                                 Comparative                                                         Example 1-1                                                                             Example 1                                            ______________________________________                                        Rolling Resistance                                                                             (100)       (100)                                            (Index)                                                                       Cornering Power  151 (101)   149 (100)                                        [kg/deg](Index)                                                               Cornering Force  433 (100)   433 (100)                                        @10°[kg](Index)                                                        Self Aligning Torque                                                                           4.5 (102)   4.4 (100)                                        Power[kg · m/deg](Index)                                             Repulsive Power Index                                                                          (99)        (100)                                            at the Time of Getting                                                        over a Bump (Index)                                                           Vertical Stiffness (Index)                                                                     21.2 (101)  21.0 (100)                                       [kg/mm]                                                                       Lateral Stiffness (Index)                                                                      15.9 (99)   16.0 (100)                                       [kg/mm]                                                                       Rolling Radius[mm](Index)                                                                      311 (100)   311 (100)                                        ______________________________________                                    

Table 5 shows the values obtained by measuring the respective assembliesof tires and wheel rims in the indoor tests carried out under theconditions that the inner pressure was 2.0 kg/cm² and the vertical loadwas 400 kg.

The rolling resistance index is indicated by the index of the the valueof the rolling resistance at a speed of 80 km/h, the cornering power bythe value of the cornering force at a slip angle of 1°, the corneringforce @10° by the value of the cornering force at a slip angle of 10°,and the self aligning torque power by the value of the self aligningtorque at a slip angle of 1°, respectively. The repulsive power index atthe time of getting over a bump is indicated by the index of the averagevalue of the repulsive power in the vertical direction and in theforward and backward direction produced when getting over a square rodof 10 mm×10 mm which is attached to a drum at a speed of 20 to 100 km/h.The index in each performance is the value taken on the assumption thatthe value in Comparative Example 1 is 100.

No degradation caused by the application of the present invention wasfound in any performance of a tire.

Industrial Applicability

An assembly of a wheel rim and a tire according to the present inventioncan be produced by a conventional method, and be mounted on a vehicle inthe same way as in a conventional tire and wheel rim. Furthermore, anassembly of the present invention enables safe running free from adanger of dislodgement of the bead portion even when the inner pressureof the tire is lowered or when the vehicle is cornering sharply.

What is claimed is:
 1. A wheel rim for use with a tire having aconventional bead construction or a bead provided with a radiallyinwardly extending toe, comprisinga well for mounting the tire and aprotrusion located axially outside the well to define acircumferentially extending annular groove disposed axially outwardthereof for receiving said radially, inwardly extending toe, a humpprovided axially outward of the annular groove, a beadbase locatedaxially outward of the hump and having a width of a conventionallystandardized dimension, and a rim flange disposed axially outward of thebeadbase, whereby the beadbase of the wheel rim can accommodate aconventional tire having a bead devoid of a radially inwardly extendingtoe or the annular groove, hump and beadbase can accommodate a tirehaving a bead with said radially inwardly extending toe.
 2. A wheel rimfor use with a tire having a conventional bead construction or a beadprovided with a radially inwardly extending toe, comprisinga well formounting a tire, a protrusion located axially outside the well, acircumferentially extending annular groove located axially outside theprotrusion, a circumferentially extending hump located axially outsidethe annular groove, and a beadbase located axially outside the hump andhaving a width of a conventionally standardized dimension, wherein thediameter Da at the top of the hump, the diameter Db at the bottom of theannular groove, and the diameter Dc at the top of the protrusion havethe following relationship:

    Db<Dc<Da,

whereby the beadbase of the wheel rim can accommodate a conventionaltire having a bead devoid of a radially inwardly extending toe, or, theannular groove, hump and beadbase can accommodate a tire having a beadwith said radially inwardly extending toe.
 3. The wheel rim according toclaim 2, wherein the width of the beadbase has conventionallystandardized dimensions.
 4. The wheel rim according to claim 3, whereinthe diameters, Da, Db and Dc and the diameter D of the beadbase satisfythe following relationships:

    -3.0 mm≦D-Da≦+5.0 mm

    +3.0 mm≦D-Dc≦+20 mm

    0 m≦D-Dc≦+5.0 mm.


5. The wheel rim according to claim 2, wherein the diameters Da, Db andDc and the diameter D of the beadbase satisfy the followingrelationships:

    -3.0 mm≦D-Da≦+5.0 mm

    +3.0 mm≦D-Dc≦+20 mm

    0 m≦D-Dc≦+5.0 mm.


6. The wheel rim according to claim 2, wherein the beadbase is taperedat an angle with respect to the axial direction of the tire so as todecrease its diameter toward the axially inside thereof.
 7. The wheelrim according to claim 2, wherein the beadbase is tapered at an anglewith respect to the axial direction of the tire so as to increase itsdiameter toward the axially inside thereof.
 8. An assembly composed of awheel rim and a tubeless tire,the tubeless tire having a pair of beadportions, at least one of which is provided with a bead core having aheel end and a radially inward extending toe end located axially insidethe bead core and further provided with an annular groove between thetoe and the heel of the bead, the wheel rim having a well for mountingthe tire, a protrusion located axially outside the well, acircumferentially extending annular groove located axially outside theprotrusion for receiving the end of the toe of the tire bead, acircumferentially extending hump located axially outside the annulargroove so as to be engaged with said groove of the tire bead and abeadbase located axially outside the hump, wherein the diameter Da atthe top of the hump, the diameter Db at the bottom of the annular grooveof the rim, and having a width of a conventionally standardizeddimension, and the diameter Dc at the top of the protrusion having thefollowing relationship:

    D<D<Da,

whereby the beadbase of the wheel rim can accommodate a conventionaltire having a bead devoid of a radially inwardly extending toe, or, theannular groove, hump and beadbase can accommodate a tire having a beadwith said radially inwardly extending toe.
 9. The assembly according toclaim 8, whereinthe axial distance between the heel end of the tire beadand the bottom of the hump groove is in a range of 50 to 150% of theaxial distance between the beadbase end of the wheel rim and the top ofthe hump, and the axial distance between the toe end and the heel end ofthe tire bead is in a range of 70 to 150% of the axial distance betweenthe beadbsae end of the wheel rim and the bottom of the annular groove.10. The assembly according to claim 8, wherein the width of the beadbasehas conventionally standardized dimensions.
 11. The assembly accordingto claim 8, wherein the diameters Da, Db and Dc and the diameter D ofthe beadbase have the following relationships:

    -3.0 mm≦D-Da≦+5.0 mm

    +3.0 mm≦D-Dc≦+20 mm

    0 m≦D-Dc≦+5.0 mm.


12. The tire-rim assembly of claim 8, wherein the axial distance W3 fromthe heel end of the tire to the bottom of the annular groove, and theaxial distance W1 from the outside end of the beadbase to the topmidpoint of the hump, and between the axial distance W4 from the heelend to the toe end and the axial distance W2 from the outside end of thebeadbase to the middle bottom of the annular groove is represented bythe expressions:

    0.5≦W3/W1≦1.2

    0.7≦W4/W2≦1.2.


13. A tire-rim assembly, comprisinga tubeless tire having a beadprovided with a bead core and a radially inwardly extending toe locatedaxially inside the bead core and a wheel rim having a well for mountingthe tire and a protrusion located axially outside the well to define,axially outwardly of the protrusion, a circumferentially extendingannular groove for receiving said radially inwardly extending toe, saidtubeless tire being provided with an annular groove disposed between thetoe and the heel of the bead, said wheel rim being provided with a humpdisposed axially outward of the annular groove to engage with saidannular groove of the tire, a beadbase located axially outside the hump,and having a width of a conventionally standardized dimension, and a rimflange located axially outward of the beadbase, said beadbase having awidth of a conventionally standardized dimension and can accommodate aconventional tire having a bead devoid of a radially inwardly extendingtoe, or, the annular groove, hump and beadbase can accommodate a tirehaving a bead with said radially inwardly extending toe.